Research Of Insecticidal Activity Of Datura Metel L. Extracts

To discover novel plant-derived products with pesticidal properties is an important way to creat new pest-management agent. It is an obvious advantage to research botannical pesticide in china for its abundant resources. On this groundwork, Datura metel L. was systematically researched. The Extract and separate technique, insecticidal effects and structure identification were made an intensive study. Results are as below:1. The Seed, Seed bark, Root, Stem and leaf of Datura metel L. were extracted with methanol, ethanol, acetone, ethyl acetate and petroleum ethe according to the different polarity of solvent. The results showed that the polarity component of Datura metel L. is not single, and the mortality of ethanol extract from the leaf of Datura metel L. against Helicoverpa armigera Hubner was 56.4% by 20mg/mL in 72h.2. Pretest for chemical constituents and screening of parasiticidally active part of Datura metel L. the possible chemical constituents of Datura metel L. were checked by means of tube-test method. The result revealed that the main components were suggested to be alkaloids.3. In titrimetric method, methyl red-bromocresol green was elected as indicator which help to get high content of total alkaloid in Datura metel L. comparing to the methyl red indicator in Chinese Pharmacopoeia (2005). The content of total alkaloids of the sample from Seed, Seed bark, Root, Stem and leaf were separately 2.31 mg/g, 0.29 mg /g, 1.62 mg/g, 1.03 mg/g and 2.53 mg/g, respectively.4. Alkaloids in Datura metel L. were extracted by cold-maceration with acid ethanol. To study the extracting process of the effective comnents of Alkaloid, the orthogonal experiment design was used for dominant selection. The results indicate that the concentration and quantity of ethanol, the rate of material to liquid and time of extraction are the influence factors. The best process set was as follow: The total alkaloid in Datura metel L.was marinated 4 times with 80% acid ethanol,PH3 and the rate of material to liquid 1:20.5. The conditions of extraction and isolation was explored by the TLC. The biological activity of Dature metel L. was tracked by antifeedant of the Helicoverpa armigera Hubner and isolated two compounds S₁ and S₂ by column chromatography, they were scopolamine and Hyoscyamine.